Electric axle with direct rotor and head spray cooling

ABSTRACT

Methods and systems are provided for an electric axle in a vehicle. The electric axle comprises an electric motor having a stator and a rotor, a coolant manifold mounted to an end plate of the rotor, wherein the coolant manifold is configured to flow coolant to rotor coolant lines extending axially through the rotor, and a spray ring comprising coolant lines coupled to the coolant manifold, wherein coolant flowing from the coolant manifold to the spray ring flows in a direction angled to an axial direction, wherein the spray ring is positioned circumferentially about axial stator end windings.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional ApplicationNo. 63/182,720, entitled “ELECTRIC AXLE WITH DIRECT ROTOR AND HEAD SPRAYCOOLING”, and filed on Apr. 30, 2021. The entire contents of theabove-listed application are hereby incorporated by reference for allpurposes.

TECHNICAL FIELD

The present description relates generally to methods and systems for anelectric axle, and, in particular, methods and systems directed tocooling an electric traction motor of the electric axle.

BACKGROUND AND SUMMARY

Electric axle assemblies and powertrain and control/electronic systemsconnected thereto require cooling and thermal management so as to removeheat from various components to improve performance characteristics ofsuch components.

Electric axle assemblies typically comprise opposing half shafts with adriven differential therebetween, with wheel ends or hubs on the outwardends of the half shafts and powertrain components connected to thedriven differential for delivering rotational power to the differentialand, accordingly, one or both of the half shafts. An electric axleassembly comprises an electric motor configured to drive, via gearing,one or more of the wheel ends, typically via driving the gearsassociated with the driven differential. The vehicle within which theelectric axle may be positioned and configured further comprises drivewheels and other powertrain components, typically including coolanthandling systems, control systems comprising electronic circuitry andone or more controllers configured for controlling the coolant handlingsystems, and other components. The one or more controllers may compriseone or more sensors and actuators configured for control of one or morecoolants

The electric motor (such as an electric traction motor drivablyconnected to the driven differential) comprises an inverter forconverting DC energy from a source of DC energy such as DC voltage froma battery (that may further comprise a charging system connected orconnectable thereto), the inverter converting the DC energy to AC energyinputs to a rotor and a stator of the electric motor. The rotor maycomprise a rotating component connectable via gearing to the drivendifferential, and the stator may comprise a stationary component affixedto structure such as a casing or enclose or housing of the electricmotor that may be fixedly connected to other non-rotating structure of apowertrain of a vehicle.

The inverter generates considerable heat and, accordingly, comprisescoolant flow paths configured for receiving a coolant (such as forexample, a coolant oil) for removing heat from the inverter electroniccomponents (e.g., switches/power field effect transistors (power FETs)).The rotor and stator (configured for rotational movement between thetwo) generate considerable heat and, accordingly preferably comprisecoolant flow paths configured for receiving a coolant (such as forexample, a coolant oil) for removing heat from areas of the rotorgenerating heat (such as the areas of the rotor proximate to thestator), and for removing heat from areas of the stator generating heat(such as areas of the stator proximate to the rotor and, especially,windings associated with the stator through which electric energy isflowed so as to generate the rotative moments and rotation of the rotorrelative to the stator).

In order to more effectively and efficiently remove heat from componentsof the electric axle, the present disclosure includes embodiments of anelectric axle comprising an electric motor having a stator and a rotor,a coolant manifold mounted to an end plate of the rotor, wherein thecoolant manifold is configured to flow coolant to rotor coolant linesextending axially through the rotor, and a spray ring comprising coolantlines coupled to the coolant manifold, wherein coolant flowing from thecoolant manifold to the spray ring flows in a direction angled to anaxial direction, wherein the spray ring is positioned circumferentiallyabout axial stator end windings.

In various embodiments, an electric axle rotor and spray ring coolingsystem comprises combinations of the features disclosed herein.

In various embodiments, an electric motor comprises cooling features asdescribed in the present disclosure.

In various embodiments, a method of cooling an electric motor used in anelectric axle, comprising flowing a coolant as described in the presentdisclosure.

In various embodiments, the methods and systems to accomplish improvedcooling includes any of the methods of cooling a rotor and/or stator ofan electric motor as described and/or illustrated herein.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE FIGURES

The advantages described herein will be more fully understood by readingan example of an embodiment, referred to herein as the DetailedDescription, when taken alone or with reference to the drawings, where:

FIG. 1 shows an exploded view of a portion of an electric axle;

FIG. 2 shows an assembly of the electric axle;

FIG. 3 shows an assembly of a cooling jacket of the electric axle;

FIG. 4 shows an electric motor including a rotor positioned within astator;

FIG. 5 shows a coolant flow block diagram;

FIG. 6 shows a cross-sectional view of the electric motor taken along anx-y plane;

FIG. 7 shows a detailed view of a cooling of the rotor;

FIG. 8 shows a view of a coolant manifold coupled to the cooling jacket;

FIG. 9 shows a view of polymer cooling rings proximal to windings of thestator;

FIG. 10 shows the coolant manifold including coolant channels coupled toan upper portion of a spray ring and into an axial shaft of the rotor;

FIG. 11 shows an opposite end of the electric motor distal to thecoolant manifold; and

FIG. 12 shows an embodiment of the spray ring.

DETAILED DESCRIPTION

The present inventors determined problems with existing designs in termsof a lack of continuous power and torque leading to low power and torquedensity in such designs, with performance requirements such that anappropriately sized electric motor would not be able to fit withincustomer-desired package specifications. The present inventorsdiscovered and determined the designs described herein, having twodifferent direct cooling methods using oil working together. First, the(coolant fluid or) oil if fed to both front and back hairpin windingheads through two cooling rings inserted between the hairpin head outerdiameter (OD) and the cooling jacket inner diameter (ID). Second, oilflowing through the rotor is sprayed from the rotor endplates to thehairpin heads inner diameter. This flow of oil is also used to cool therotor lamination stacks and ensure a controlled magnet temperature. Theoil is then flowing down by gravity and to a sump cavity, where anelectrical pump and oil filtration feed the gear box or the gears/geartrain may be cooled directly (see boundary diagram shown in FIG. 5).

FIG. 1 shows an exploded view 100 of a portion of an electric axle 110,according to embodiments. As shown, an electric motor 120 comprising a(hairpin type) cylindrical stator 122 (core) and a rotor 124 positionedtherein, may be enveloped by a cooling jacket 126. The cooling jacket126 (with rotor and stator positioned therein) may be fit within themotor enclosure/housing 112. The channels shown circumferentially on thecooling jacket, combined with the inside surface of theenclosure/housing 112 (or carrier/case) provide paths for a coolantfluid (such as water or other coolant fluid composition) to flow acrossthe circumferential surfaces of the cooling jacket, to thereby removeheat from the stator core positioned therewithin. Also as shown in theexploded view of FIG. 1, a drive shaft 130 of the electric motor (alongthe motor's axis of rotation) may be gearably connected to adifferential 140, via gears 132 in such a manner as to drive half shafts(and wheel ends) drivably connected thereto. An inverter 150 is shownthat may be affixed to the carrier/case 112, the inverter 150 providingelectrical energy to the rotor 124 and stator 122.

FIG. 2 shows an assembly 200 of the electric axle 110, according toembodiments. As shown, an exemplary electric axle may comprise wheelends, half shafts, a differential, and gears connected to the outputshaft of an electric motor. As such, components previously introducedmay be similarly numbered in this and subsequent figures.

FIG. 3 shows an embodiment 300 of the cooling jacket 126 as shown inFIG. 1, according to embodiments. The jacket is shown withcircumferentially oriented ribs 302 that, when coupled with the interiorsurface of the carrier/case within which the jacket assembly insertablyfits, create channels for coolant fluid to flow across the exteriorsurface of the cooling jacket 126, thereby removing heat therefrom(effectively pulling heat away from the stator core material surroundedby the cooling jacket). A coolant manifold 310 is shown on the end ofthe cooling jacket 126. In one example, the coolant manifold 310 is anend mounted coolant manifold. The end mounted coolant manifold 310receives coolant fluid (such as oil) and supplies the oil to both achannel within the rotor shaft (for directly cooling the rotor) and achannel within the carrier/case (for supplying oil to a pair of coolingrings/spray rings situated proximate each end of the stator core so thatthe coolant oil may be sprayed radially inward onto the head outsidediameter (or head OD, or end windings) of the stator.

The coolant manifold 310 may include a spray arm 312 extending radiallyoutward from a center therefrom. A passage may extend from the centerand through an entirety of the spray arm 312. The passage may flowcoolant to multiple axial coolant passages arranged within the rotor andthe cooling jacket 126.

FIG. 4 shows the electric motor 120 including the rotor 124 positionedwithin the stator 122, as shown in the exploded view of FIG. 1,according to embodiments. The rotor is surrounded by the stator core.The stator may comprise hairpin windings 402 that, as shown, extend outof the stator core axially at each end, the extending portions of thewindings referred to as end windings or stator head. The axially opposedend windings (or heads) each have an inside diameter (ID) and an outsidediameter (OD).

FIG. 5 shows a block diagram 500 showing coolant flows, according toembodiments. The block diagram 500 shown comprises exemplary coolantflows and may be referred to as a boundary diagram. As shown, the e-axle110 (electric axle) preferably comprises a carrier having a gear train132 therewithin and having an inverter 150 atop the carrier 112,positioned immediately above the motor/traction motor 120 portion of theassembly. Oil (or coolant fluid) flows from a water to oil heatexchanger 502 into the end mount coolant feed manifold 310 (as in FIG.3) to provide oil into channel in a rotor shaft 324. The oil enteringthe rotor shaft 324 preferably may flow to the middle of the rotor,axially mid-way between the rotor ends and stator end windings/heads,where the oil then flows through radially outward directed channelswithin the rotor 124 to channels running axially (parallel to the axisof rotation) along radially outward portions of the rotor 124 beforeexiting the rotor 124 via rotor end plates and orifices sized anddirected therein to direct cooling oil onto the end windings innerdiameter (head ID) thereby cooling the end windings ID. The oil thengravitationally flows downward to a motor sump 510 and potentiallythrough portions of the gear train housing/cavity, where a pump 320 thensends the oil back to the water to oil heat exchanger (upper right inthe diagram shown in FIG. 5).

From the coolant feed manifold (such as in FIG. 3), coolant oil is also(in addition to the rotor shaft channel) fed into the coolingrings/spray rings either directly via channels into the spray ringstructure (for the spray ring proximate the coolant feed manifold) or(for the spray ring positioned between the carrier and/or cooling jacketand the stator end windings (head OD) axially opposite from the coolantfeed manifold, the oil preferably flows through at least on channel inthe carrier and is fed into the spray ring. Orifices/holes in the sprayrings (such as those illustrated in FIG. 12) are preferably sized anddirected/oriented so as to spray coolant oil onto the end windings OD(head OD).

In this way, coolant oil is used to both directly cool the rotor and theend windings ID, and cool the end windings OD via the coolingrings/spray rings. Further, a cooling is provided by the cooling jacketvia water ethylene glycol (WEG) cooling lines 504. The cooling linesprovide coolant (such as water) to the coolant jacket channels tothereby cool the circumferential surfaces surrounding the stator core.The WEG cooling lines 504 extend (as shown in FIG. 5) to the water tooil heat exchanger 502. The WEG cooling lines 504 may be coupled to avehicle cooling system 506.

FIG. 6 is a cut view 600 of the electric motor 120, as shown in FIG. 1,according to embodiments. The motor may comprise the hairpin type stator122 with hairpin connections at one (axial) end of the stator, and arereferred to as end windings 402 (or the stator heads). Each of thehairpins may comprise hairpin wire/magnetic wire of rectangularcross-section. In one example, the electric motor 120 is an AC motor.The motor comprises what may be referred to as stator hybrid cooling,whereby cooling is accomplished using front and back end winding oilcooling, as well as WEG jacket cooling (for active length cooling alongthe axial exterior surfaces of the stator core, via the cooling jacketand the cooling fluid channels circumferentially disposed thereon).Further, rotor cooling (shown in FIG. 7) is provided via direct oilcooling of the rotor core (via cooling oil fed into the rotor shaft aspreviously described).

FIG. 7 shows a more detailed view 700 of the rotor cooling, according toembodiments. As previously described, cooling fluid (such as oil) isreceived into the rotor shaft 324 as shown. The channel extends to themid-point between the axial ends of the rotor shaft 324, whereafterradial channels 724, 726 permit cooling oil to travel radially outwardinto axially oriented channels 742, 744 running axially toward the axialends of the rotor 124. End plates 730 and 732 with holes/orifices 734,736 permit the oil to be sprayed outward and radially outward onto thehead ID/end windings inside diameter. The rotor shaft 324 may include arotor shaft passage 722 extending in an axial direction toward theradial channels 724, 726. The rotor shaft passage 722 may be fluidlycoupled to the coolant manifold.

FIG. 8 shows a closer detail perspective view 800 of the end mountedcoolant manifold 310 (or rotor coolant feed manifold, or rotor and sprayring coolant feed manifold) assembled to the cooling jacket as in FIG. 3and further assembled into the outer case/enclosure housing shown in theexploded view of FIG. 1, according to embodiments. As illustrated, thecoolant manifold 310 is inserted into the cooling jacket 126, whereinthe cooling jacket 126 is physically coupled the housing 112 via aplurality of fasteners 802. The cooling jacket 126 further comprises aninterface 804 which is configured to couple to a housing cover, such ashousing cover 160 of FIG. 1. The radial arm 312 extends in a directiontoward a gear train (e.g., gears 132) and is adjacent to the interface804.

FIG. 9 shows a view 900 showing stator end windings 402 radially betweena spray ring and a rotor endplate, according to embodiments. As shown,the coolant feed manifold 310 provides a channel for supplying coolingoil up into the carrier for supply of one or both cooling rings 902 and904. As shown, a first channel 906 runs axially across the carrier andincludes auxiliary channels for supplying cooling oil into both thefirst cooling ring 902 and the second cooling ring 904, wherein thefirst cooling ring 902 is closer to the coolant feed manifold 310 thanthe second cooling ring 904. The first channel 906 may be fluidlycoupled to a radial arm passage 912. The radial arm passage 912 may flowcoolant to each of the first channel 906 and a second channel, whereinthe second channel is identical to the rotor shaft passage 722. Thefirst channel 906 and the rotor shaft passage 722 are parallel to oneanother and extend in an axial direction.

FIG. 10 illustrates a detailed view 1000 of the first cooling ring 902adjacent to the radial arm 312 and the rotor end plate 730. The holes inthe cooling rings are sized and oriented so as to spray cooling oil ontothe outer diameter of the end windings (or head OD) of the stator 122.The oil then gravitationally flows down into the sump system below therotor and stator. Also shown in FIGS. 10 and 11) are channels throughwhich cooling oil is supplied directly into the rotor shaft, throughradially oriented passages that then connect to channels extendingaxially (in a number of channels positioned across the circumference ofthe rotor) which end with the holes in the rotor end plates so that theoil sprays outward and preferably is directed to the end windings innerdiameter (head ID) so as to further cool the stator end windings. Theoil exiting the rotor end plates and onto the stator end windings thengravitationally flows downward into the motor sump system.

The radial arm passage 912 may flow coolant to an angled passage 1002fluidly coupled to the first cooling ring 902. The radial arm passage912 may thus be bifurcated and configured to flow coolant to each of theangled passage 1002 and the first passage 906 at a radially outer end.The radial arm passage 912 may be further configured to flow coolant tothe rotor shaft passage 722 at a radially inner end.

FIG. 10 shows a view 1000 illustrating the end mounted coolant feedmanifold with coolant channels to a top of the spray ring and into theaxial shaft of the rotor at a first end, according to embodiments.

FIG. 11 shows a view 1100 illustrating the end mounted coolant feedmanifold with coolant channels to a top of the spray ring and into theaxial shaft of the rotor at a second end, opposite the first end,according to embodiments.

FIG. 12 shows an enlarged detail view 1200 of a spray ring 1202, whichmay be identical to the first spray ring 902 or the second spray ring904 of FIG. 9, according to embodiments. As shown, the spray ring 1202comprises at least one channel (formed between an exteriorsurface/outside diameter surface and the inner surface of the coolingjacket) and comprises a plurality of orifices 1204 or holes throughwhich cooling oil may be sprayed and directed toward the end windings ofthe stator. The plurality of orifices 1204 may extend around a portionof the circumference of the spray ring 1202. In one example, theplurality of orifices 1204 extend around less than half thecircumference of the spray ring 1202. Additionally or alternatively, theplurality of orifices 1204 may extend around an entirety of thecircumference of the spray ring 1202.

The plurality of orifices 1204 may be configured to spray lubricanttoward an outer diameter of the rotor end windings. Additionally oralternatively, the plurality of orifices 1204 may include a uniform flowthrough area. In other examples, the plurality of orifices 1204 mayinclude a non-uniform flow through area configured to acceleratelubricant flow toward the end windings.

FIGS. 1-4 and 6-12 are shown approximately to scale. However, otherrelative dimensions may be used if desired.

FIGS. 1-4 and 6-12 show example configurations with relative positioningof the various components. If shown directly contacting each other, ordirectly coupled, then such elements may be referred to as directlycontacting or directly coupled, respectively, at least in one example.Similarly, elements shown contiguous or adjacent to one another may becontiguous or adjacent to each other, respectively, at least in oneexample. As an example, components laying in face-sharing contact witheach other may be referred to as in face-sharing contact. As anotherexample, elements positioned apart from each other with only a spacethere-between and no other components may be referred to as such, in atleast one example. As yet another example, elements shown above/belowone another, at opposite sides to one another, or to the left/right ofone another may be referred to as such, relative to one another.Further, as shown in the figures, a topmost element or point of elementmay be referred to as a “top” of the component and a bottommost elementor point of the element may be referred to as a “bottom” of thecomponent, in at least one example. As used herein, top/bottom,upper/lower, above/below, may be relative to a vertical axis of thefigures and used to describe positioning of elements of the figuresrelative to one another. As such, elements shown above other elementsare positioned vertically above the other elements, in one example. Asyet another example, shapes of the elements depicted within the figuresmay be referred to as having those shapes (e.g., such as being circular,straight, planar, curved, rounded, chamfered, angled, or the like).Additionally, elements co-axial with one another may be referred to assuch, in one example. Further, elements shown intersecting one anothermay be referred to as intersecting elements or intersecting one another,in at least one example. Further still, an element shown within anotherelement or shown outside of another element may be referred as such, inone example. In other examples, elements offset from one another may bereferred to as such.

The disclosure provides support for an electric axle including anelectric motor having a stator and a rotor, a coolant manifold mountedto an end plate of the rotor, wherein the coolant manifold is configuredto flow coolant to rotor coolant lines extending axially through therotor, and a spray ring comprising coolant lines coupled to the coolantmanifold, wherein coolant flowing from the coolant manifold to the sprayring flows in a direction angled to an axial direction, wherein thespray ring is positioned circumferentially about axial stator endwindings. A first example of the electric axle further includes wherethe coolant manifold is pressed into a cooling jacket. A second exampleof the electric axle, optionally including the first example, furtherincludes where the coolant jacket comprises circumferentially orientedribs. A third example of the electric axle, optionally including one ormore of the previous examples, further includes where the spray ring isa first spray ring, further comprising a second spray ring arranged atan end of the rotor opposite the first spray ring and distal to thecoolant manifold, and wherein the first spray ring and the second sprayring direct coolant toward an outer diameter of the end windings. Afourth example of the electric axle, optionally including one or more ofthe previous examples, further includes where the coolant manifold isfluidly coupled to a rotor channel arranged in a shaft of the rotor,wherein the rotor channel extends to a mid-point of the shaft and flowscoolant to an inner axial channel radially distal to the rotor channelvia radial channels. A fifth example of the electric axle, optionallyincluding one or more of the previous examples, further includes wherethe end plate is a first end plate arranged at a first end of the rotorproximal to the coolant manifold, further comprising a second end platearranged at a second end distal to the coolant manifold, wherein thefirst end plate and the second end plate spray coolant toward an innerdiameter of the end windings. A sixth example of the electric axle,optionally including one or more of the previous examples, furtherincludes where the coolant manifold is fluidly coupled to an outer axialchannel arranged between the stator and a housing of the electric motor.A seventh example of the electric axle, optionally including one or moreof the previous examples, further includes where the coolant manifoldextends outside of a housing of the electric motor.

The disclosure further provides support for a system including anelectric axle, an electric motor including a stator and a rotor arrangedin a housing, a coolant manifold inserted through a first end cap of therotor, wherein the coolant manifold is fluidly coupled to a firstchannel arranged between a cooling jacket and the stator and a secondchannel arranged in a rotor shaft, the coolant manifold comprising aradial arm extending from a center of the coolant manifold to the secondchannel, and a first spray ring arranged adjacent to the coolantmanifold and the first end cap and a second spray ring arranged adjacentto a second end cap, the second end cap arranged at an end of the rotoropposite the first end cap, the first spray ring and the second sprayring configured direct coolant from the first channel and the secondchannel to an outer diameter of stator end windings. A first example ofthe system further includes where the radial arm comprises a bifurcatedchannel configured to flow coolant to each of the second channel and thefirst spray ring. A second example of the system, optionally includingthe first example, further includes where an angled passage extends fromthe first spray ring to the bifurcated channel. A third example of thesystem, optionally including one or more of the previous examples,further includes where a motor sump system configured to receive coolantthat has been flowed onto the stator end windings, the sump systemcomprising a pump for returning the coolant to a heat exchanger,whereafter the coolant returns to the coolant manifold. A fourth exampleof the system, optionally including one or more of the previousexamples, further includes where the coolant manifold is arrangedoutside of the housing. A fifth example of the system, optionallyincluding one or more of the previous examples, further includes wherethe second channel extends to a mid-section of the shaft, and wherein aremainder of the shaft is solid. A sixth example of the system,optionally including one or more of the previous examples, furtherincludes where the second channel comprises connecting passages thatdirect coolant radially outward to an inner axial channel fluidlycoupled to the first end plate and the second end plate. A seventhexample of the system, optionally including one or more of the previousexamples, further includes where the first end plate and the second endplate spray coolant to an inner diameter of the rotor end windings.

The disclosure further provides support for an electric axle includingan electric motor having a stator and a rotor, rotor coolant linesextending axially through the rotor so as to receive coolant via an endmounted coolant manifold and flow the coolant axially within the rotorto radially directed flow lines which connect with coolant heat transferlines running axially along radially outward channels within theradially outward portion of the rotor so as to transfer heat therefrom,the radially outward rotor channels flowing coolant axially toward theaxial ends of the rotor, and out of the rotor ends via directed floworifices, directing coolant onto axial end windings of the stator, sprayring coolant lines feeding coolant to coolant spray rings positionedcircumferentially about each of the axial stator end windings, thecoolant spray rings receiving coolant from coolant lines within anelectric motor carrier or carrier coolant manifold, the carrier coolantmanifold further configured to transfer heat from the radially outwardcircumferential surfaces of the stator core, and the spray ringsreceiving coolant and flowing the coolant out of the interiorcircumference of the spray rings via spray ring directed flow orifices,directing coolant onto axial end windings of the stator, and a motorsump system configured to receive coolant that has been flowed onto thestator end windings, the sump system having a pump for returning thecoolant to a heat exchanger, whereafter the coolant returns to thecoolant manifold. A first example of the electric axle further includeswhere the end mounted coolant manifold is coupled to a coolant jacketphysically coupled to the rotor. A second example of the electric axle,optionally including the first example, further includes where the endmounted coolant manifold comprises a spray arm extending from a centerof the end mounted coolant manifold to a bifurcated passage. A thirdexample of the electric axle, optionally including one or more of theprevious examples, further includes where the bifurcated passage directscoolant to a radially outward channel and an angled channel, wherein theradially outward channel is arranged between the stator and the carrier,and wherein the angled channel sprays coolant onto an outer diameter ofthe axial end windings.

The disclosure further provides support for an electric axle includingan electric motor having a stator and a rotor, a coolant manifoldmounted to an end plate of the rotor, wherein the coolant manifold isconfigured to flow coolant to rotor coolant lines extending axiallythrough the rotor, and a first spray ring arranged adjacent to thecoolant manifold and a second spray ring arranged distally to thecoolant manifold, wherein the first spray ring receives coolant from thecoolant manifold via an interior passage and the second spray ringreceives coolant from the coolant manifold via an outer passage. A firstexample of the electric axle further includes where the first spray ringand the second spray ring are identical. A second example of theelectric axle, optionally including the first example, further includeswhere the first spray ring and the second spray ring comprise aplurality of orifices extending around a circumference of the firstspray ring and the second spray ring. A third example of the electricaxle, optionally including one or more of the previous examples, furtherincludes where the plurality of orifices extends around less than halfthe circumference of the first spray ring and the second spray ring. Afourth example of the electric axle, optionally including one or more ofthe previous examples, further includes where the plurality of orificesis arranged on only an upper portion of the first spray ring and thesecond spray ring. A fifth example of the electric axle, optionallyincluding one or more of the previous examples, further includes wherethe first spray ring and the second spray ring comprise a channelarranged between opposite edges. A sixth example of the electric axle,optionally including one or more of the previous examples, furtherincludes where the interior passage is angled relative to a radial andan axial direction, and wherein the outer passage is parallel to theaxial direction. A seventh example of the electric axle, optionallyincluding one or more of the previous examples, further includes wherethe first spray ring and the second spray ring are configured to spraycoolant onto an outer diameter of stator end windings. An eighth exampleof the electric axle, optionally including one or more of the previousexamples, further includes where an inner diameter of stator endwindings is sprayed with coolant via end plates of the rotor, whereinthe end plate is one of the end plates.

The disclosure further provides support for a system including anelectric axle, an electric motor including a stator and a rotor arrangedin a housing, a coolant manifold inserted through a first end cap of therotor, wherein the coolant manifold is fluidly coupled to a firstpassage arranged in a rotor shaft and a second passage arranged betweena cooling jacket and the stator, the coolant manifold comprising aradial arm extending from a center of the coolant manifold to the secondchannel, and a first spray ring arranged adjacent to the coolantmanifold and the first end cap and a second spray ring arranged adjacentto a second end cap, the second end cap arranged at an end of the rotoropposite the first end cap, the first spray ring and the second sprayring configured direct coolant from the second channel to an outerdiameter of stator end windings via a plurality of orifices. A firstexample of the system further includes where the second passage isangled relative to a radial direction and an axial direction. A secondexample of the system, optionally including the first example, furtherincludes where the first passage is parallel to the axial direction. Athird example of the system, optionally including one or more of theprevious examples, further includes where the first spray ring and thesecond spray ring are pressed against an interior surface of the coolantjacket, wherein the coolant manifold is inserted into an opening of thecoolant jacket. A fourth example of the system, optionally including oneor more of the previous examples, further includes where the pluralityof orifices is arranged on only an upper portion of the first spray ringand the second spray ring. A fifth example of the system, optionallyincluding one or more of the previous examples, further includes whereeach of the plurality of orifices comprises a uniform cross-sectionalflow through area. A sixth example of the system, optionally includingone or more of the previous examples, further includes where theplurality of orifices is arranged at a bottom of a recess of the firstspray ring and the second spray ring.

The disclosure further provides support for an electric axle includingan electric motor having a stator and a rotor, rotor coolant linesextending axially through the rotor so as to receive coolant via an endmounted coolant manifold and flow the coolant axially within the rotorto radially directed flow lines which connect with coolant heat transferlines running axially along radially outward channels within theradially outward portion of the rotor so as to transfer heat therefrom,the radially outward rotor channels flowing coolant axially toward theaxial ends of the rotor, and out of the rotor ends via directed floworifices, directing coolant onto axial end windings of the stator, sprayring coolant lines feeding coolant to coolant spray rings positionedcircumferentially about each of the axial stator end windings, thecoolant spray rings receiving coolant from coolant lines within anelectric motor carrier or carrier coolant manifold, the carrier coolantmanifold further configured to transfer heat from the radially outwardcircumferential surfaces of the stator core, and the spray ringsreceiving coolant and flowing the coolant out of the interiorcircumference of the spray rings via spray ring directed flow orifices,directing coolant onto axial end windings of the stator, the spray ringcoolant lines including an angled passage coupled to a first spray ringand an outer radial passage coupled to a second spray ring, and a motorsump system configured to receive coolant that has been flowed onto thestator end windings, the sump system having a pump for returning thecoolant to a heat exchanger, whereafter the coolant returns to thecoolant manifold. A first example of the electric axle further includeswhere the first spray ring and the second spray ring comprise a recessarranged between outer edges, and wherein a plurality of orifices isarranged at a bottom of the recess. A second example of the electricaxle, optionally including the first example, further includes where therecess extends around an entire circumference of the first spray ringand the second spray ring, and wherein the plurality of orifices extendsaround less than half a circumference of the first spray ring and thesecond spray ring. A third example of the electric axle, optionallyincluding one or more of the previous examples, further includes whereeach of the plurality of orifices is identical.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1. An electric axle comprising: an electric motor having a stator and arotor; a coolant manifold mounted to an end plate of the rotor, whereinthe coolant manifold is configured to flow coolant to rotor coolantlines extending axially through the rotor; and a spray ring comprisingcoolant lines coupled to the coolant manifold, wherein coolant flowingfrom the coolant manifold to the spray ring flows in a direction angledto an axial direction, wherein the spray ring is positionedcircumferentially about axial stator end windings.
 2. The electric axleof claim 1, wherein the coolant manifold is pressed into a coolingjacket.
 3. The electric axle of claim 2, wherein the coolant jacketcomprises circumferentially oriented ribs.
 4. The electric axle of claim1, wherein the spray ring is a first spray ring, further comprising asecond spray ring arranged at an end of the rotor opposite the firstspray ring and distal to the coolant manifold, and wherein the firstspray ring and the second spray ring direct coolant toward an outerdiameter of the end windings.
 5. The electric axle of claim 1, whereinthe coolant manifold is fluidly coupled to a rotor channel arranged in ashaft of the rotor, wherein the rotor channel extends to a mid-point ofthe shaft and flows coolant to an inner axial channel radially distal tothe rotor channel via radial channels.
 6. The electric axle of claim 5,wherein the end plate is a first end plate arranged at a first end ofthe rotor proximal to the coolant manifold, further comprising a secondend plate arranged at a second end distal to the coolant manifold,wherein the first end plate and the second end plate spray coolanttoward an inner diameter of the end windings.
 7. The electric axle ofclaim 5, wherein the coolant manifold is fluidly coupled to an outeraxial channel arranged between the stator and a housing of the electricmotor.
 8. The electric axle of claim 1, wherein the coolant manifoldextends outside of a housing of the electric motor.
 9. A system,comprising: an electric axle; an electric motor including a stator and arotor arranged in a housing; a coolant manifold inserted through a firstend cap of the rotor, wherein the coolant manifold is fluidly coupled toa first channel arranged between a cooling jacket and the stator and asecond channel arranged in a rotor shaft, the coolant manifoldcomprising a radial arm extending from a center of the coolant manifoldto the second channel; and a first spray ring arranged adjacent to thecoolant manifold and the first end cap and a second spray ring arrangedadjacent to a second end cap, the second end cap arranged at an end ofthe rotor opposite the first end cap, the first spray ring and thesecond spray ring configured direct coolant from the first channel andthe second channel to an outer diameter of stator end windings.
 10. Thesystem of claim 9, wherein the radial arm comprises a bifurcated channelconfigured to flow coolant to each of the second channel and the firstspray ring.
 11. The system of claim 10, wherein an angled passageextends from the first spray ring to the bifurcated channel.
 12. Thesystem of claim 9, further comprising a motor sump system configured toreceive coolant that has been flowed onto the stator end windings, thesump system comprising a pump for returning the coolant to a heatexchanger, whereafter the coolant returns to the coolant manifold. 13.The system of claim 9, wherein the coolant manifold is arranged outsideof the housing.
 14. The system of claim 9, wherein the second channelextends to a mid-section of the shaft, and wherein a remainder of theshaft is solid.
 15. The system of claim 14, wherein the second channelcomprises connecting passages that direct coolant radially outward to aninner axial channel fluidly coupled to the first end plate and thesecond end plate.
 16. The system of claim 15, wherein the first endplate and the second end plate spray coolant to an inner diameter of therotor end windings.
 17. An electric axle comprising: an electric motorhaving a stator and a rotor; rotor coolant lines extending axiallythrough the rotor so as to receive coolant via an end mounted coolantmanifold and flow the coolant axially within the rotor to radiallydirected flow lines which connect with coolant heat transfer linesrunning axially along radially outward channels within the radiallyoutward portion of the rotor so as to transfer heat therefrom; theradially outward rotor channels flowing coolant axially toward the axialends of the rotor, and out of the rotor ends via directed flow orifices,directing coolant onto axial end windings of the stator; spray ringcoolant lines feeding coolant to coolant spray rings positionedcircumferentially about each of the axial stator end windings, thecoolant spray rings receiving coolant from coolant lines within anelectric motor carrier or carrier coolant manifold, the carrier coolantmanifold further configured to transfer heat from the radially outwardcircumferential surfaces of the stator core, and the spray ringsreceiving coolant and flowing the coolant out of the interiorcircumference of the spray rings via spray ring directed flow orifices,directing coolant onto axial end windings of the stator; and a motorsump system configured to receive coolant that has been flowed onto thestator end windings, the sump system having a pump for returning thecoolant to a heat exchanger, whereafter the coolant returns to thecoolant manifold.
 18. The electric axle of claim 17, wherein the endmounted coolant manifold is coupled to a coolant jacket physicallycoupled to the rotor.
 19. The electric axle of claim 17, wherein the endmounted coolant manifold comprises a spray arm extending from a centerof the end mounted coolant manifold to a bifurcated passage.
 20. Theelectric axle of claim 19, wherein the bifurcated passage directscoolant to a radially outward channel and an angled channel, wherein theradially outward channel is arranged between the stator and the carrier,and wherein the angled channel sprays coolant onto an outer diameter ofthe axial end windings.